code: def test_load_from_checkpoint(self):
      scheduler = self.get_scheduler()
  
      for epoch in range(3):
          for step in range(10):
              scheduler.step_batch()
          scheduler.step()
  
      assert scheduler.last_epoch == 2
      assert scheduler._current_scheduler is not None
      assert scheduler._current_scheduler.total_steps == 50
      assert scheduler._current_scheduler.base_values[0] == 0.5
  
      state_dict = scheduler.state_dict()
      new_scheduler = self.get_scheduler()
      new_scheduler.load_state_dict(state_dict)
  
      assert new_scheduler.last_epoch == 2
      assert new_scheduler._current_scheduler is not None
      assert new_scheduler._current_scheduler.total_steps == 50
      assert (
          new_scheduler._current_scheduler.base_values[0] == 0.5
      ), state_dict
  
file_path: allennlp/tests/training/learning_rate_schedulers/combined_test.py
imports: import torch
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.common.params import Params
  from allennlp.training.learning_rate_schedulers import LearningRateScheduler, CombinedLearningRateScheduler, PolynomialDecay
  from allennlp.training.optimizers import Optimizer
label_desc: Use image node_id 4 for calling the TestCombinedLRScheduler obj's underlying member method code with example usage: obj.test_load_from_checkpoint() without return types